Vehicle navigation systems determine a current position of the vehicle relative to a database of roads and display a recommended route via the database of roads to a destination selected by the user. Some navigation systems have provided algorithms for transforming data in the database into a 3-dimensional perspective view which is more easily understood by many users. In one such system, the navigation system selects a point at some elevation above the vehicle""s current position, or slightly behind the vehicle""s current position, from which to calculate the perspective view of the roads.
In some situations, it can be difficult to discern a specific road from the display. For example, at an intersection of two roads at an acute angle, it may be difficult to discern the two roads in a perspective view. Also, where there are two or more intersections in close proximity, it may be difficult to discern the location of one road versus another in a perspective view. Further, complex intersections, such as rotaries, with multiple intersections of roads in close proximity may not be easy to understand from the perspective view.
The present invention provides a vehicle navigation system or route guidance system with improved perspective view display. Generally, the navigation system displays a perspective view of an intersection indicating the next maneuver to be performed by the driver along the recommended route. The navigation system displays the intersection at an angle relative to xe2x80x9cearth.xe2x80x9d Based upon the complexity of the intersection displayed, the angle is increased to provide a more xe2x80x9coverheadxe2x80x9d view. The increased angle of the perspective view improves the understanding of the roads in the intersection.
For example, if there are many roads intersecting in the area to be displayed, increasing the viewing angle will provide more space on the screen between the roads, thereby increasing the understanding of the intersection. Further, the maneuver which is being recommended by the navigation system (such as by indicating an arrow on one of the intersecting roads) is more readily perceived.
The display displays a horizon and sky in the perspective view. Based upon the time of day (and time of year), which can be gathered from the GPS system, the color of the sky changes. During the day, the sky in the display is preferably a shade of blue which gradually shifts to black at night and back to blue. In this manner, the display assists the observer in associating the perspective view on the display with what the observer sees outside in front of the vehicle.